Contagion

Contagion is a chaos spell that applies a chaos damage over time effect to all enemies in the area, and spreads itself when an enemy dies. Contagion interacts favourably with , a skill that deals heavy chaos damage over time and is spread by Contagion.

Skill functions and interactions

• Modifiers to Spell Damage apply to this skill's Damage Over Time Effect: Modifiers to spell damage only affect the damage over time effect of Contagion granted by the gem and do not affect other sources of damage over time caused by the skill.
• : When an enemy affected by both Contagion and Essence Drain dies, the resulting Contagion proc will spread both effects. This is a unique interaction. Contagion will not spread other damage over time effects.
• Duration: Increases and reductions to duration function normally. The duration of Contagion and associated degeneration effects () is not reset when spread to other enemies on death.

• Area of Effect: Modifiers to area of effect affect both the skill radius and spread radius of Contagion. Modifiers to area damage (such as ) do not apply.

• On hit effects: Contagion does not hit, and therefore cannot activate the effects of supports such as .

Gem level progression

Level				Mana Cost	Chaos Damage per sec	Exp.	Total Exp.
1	4	0	0	5	3.5	0	0
2	6	0	0	6	4.3	841	841
3	9	0	17	6	5.7	3099	3940
4	12	14	21	7	7.4	7433	11373
5	16	18	26	8	10.2	22895	34268
6	20	22	31	9	13.6	49725	83993
7	24	25	37	10	18	95714	179707
8	28	29	42	11	23.3	169595	349302
9	32	33	47	11	29.9	283759	633061
10	36	36	52	12	38.1	453996	1087057
11	40	40	58	13	48.1	703128	1790185
12	44	44	63	14	60.3	1061223	2851408
13	48	48	68	15	75.2	2065870	4917278
14	52	51	74	16	93.3	2507110	7424388
15	55	54	78	16	109.5	2573731	9998119
16	58	57	82	17	128.1	7611351	17609470
17	61	60	86	18	149.6	13437908	31047378
18	64	62	90	18	174.4	25052147	56099525
19	67	65	94	19	203	43869436	99968961
20	70	68	98	20	235.9	242081178	342050139
21	72	70	100	20	260.5	N/A	N/A
22	74	N/A	N/A	21	287.5	N/A	N/A
23	76	N/A	N/A	21	317.2	N/A	N/A
24	78	N/A	N/A	21	349.7	N/A	N/A
25	80	N/A	N/A	22	385.4	N/A	N/A
26	82	N/A	N/A	22	424.5	N/A	N/A
27	84	N/A	N/A	23	467.3	N/A	N/A
28	86	N/A	N/A	23	514.3	N/A	N/A
29	88	N/A	N/A	24	565.7	N/A	N/A
30	90	N/A	N/A	24	621.9	N/A	N/A
31	91	N/A	N/A	24	652	N/A	N/A
32	92	N/A	N/A	25	683.5	N/A	N/A
33	93	N/A	N/A	25	716.5	N/A	N/A
34	94	N/A	N/A	25	750.9	N/A	N/A
35	95	N/A	N/A	25	787	N/A	N/A
36	96	N/A	N/A	25	824.7	N/A	N/A
37	97	N/A	N/A	26	864.1	N/A	N/A
38	98	N/A	N/A	26	905.4	N/A	N/A
39	99	N/A	N/A	26	948.5	N/A	N/A
40	100	N/A	N/A	26	993.6	N/A	N/A

Related helmet enchantments

The following helmet enchantments affect Contagion.

Alternate skill effects

Contagion has the following alternate skill effects:

Version history

Version	Changes
3.13.0	Now has a base radius of 17 (from 20).
3.12.0	Now has alternative quality.
3.8.0	No longer gains additional radius as the gem levels (previously gained +4 radius by gem level 20).
3.6.0	Mana Cost at gem level 1 is now 5 (was 11). Mana Cost at gem level 20 is now 20 (was 28). Can now affect up to 40 targets per cast (from 20).
2.6.0	Contagion's radius has increased from 18 to 20 units.
2.2.1d	Fixed an instance crash with Contagion.
2.1.1c	Fixed an instance crash with [...] Contagion.
2.1.1b	Fixed a bug where Contagion could be cast and spread through walls.
2.1.1	Contagion can now be supported by Iron Will.
2.1.0	Added to the game.